Structure of reinforcing ribs around the bottle waist

ABSTRACT

The title of the invention is the structure of reinforcing ribs around bottle waist. The purpose of the invention is to achieve enhanced buckling strength in a bottle of a reinforcing rib structure comprising a horizontal concave rib in the waist portion of the bottle body and the reinforcing ribs disposed vertically at regular intervals along the circumference of this horizontal concave rib.  
     The means to achieve this purpose is to give the bottle a configuration comprising:  
     A bottle composed of neck ( 1 ), shoulder ( 2 ), body ( 3 ), and bottom ( 4 ), said body ( 3 ) consisting of an upper body ( 7 ), a lower body ( 8 ), and the waist ( 9 ) between the upper and lower bodies;  
     A horizontal concave rib ( 16 ) forming itself into said waist ( 9 ) and consisting of a concave wall connected to the lower end of said upper body ( 7 ), a concave wall connected to said lower body ( 8 ), and the bottom ( 16   c ) of the concave between these upper and lower concave walls; and  
     Reinforcing ribs ( 18 ), which are disposed in the vertical direction at regular intervals along the circumference of said horizontal concave rib ( 16 );  
     Wherein said vertical reinforcing ribs ( 18 ) are designed to be narrow in the central part and wide at either or both ends, where each of said ribs is integrated with the peripheries of concave walls of said horizontal concave rib ( 16 ).

TECHNICAL FIELD

[0001] This invention relates to the structure of reinforcing ribs disposed around bottle waist, and particularly to the reinforcing ribs combined with a horizontal concave rib and disposed vertically inside the horizontal concave rib that forms the waist of a bottle.

BACKGROUND OF THE INVENTION

[0002] It has been conventionally well known for bottles to have a horizontal concave rib that forms the waist of the bottle so as to reinforce the bottle body and to get an easy grip of the bottle.

[0003] However, conventional bottles had a problem in that the horizontal concave rib did not contribute to the reinforcement of buckling strength, even though the rib could have improved the toughness of the bottle body.

[0004] For the solution of this problem, it is proposed that vertical reinforcing ribs are disposed circumferentially along the horizontal concave rib at regular intervals, as shown in FIG. 5, so as to enhance the buckling strength in the waist portion of a bottle.

[0005] In FIG. 5, the sign (Aa) denotes a conventional bottle comprising the neck la, the shoulder 2 a, the body 3 a, and the bottom 4 a. Also, the sign (a) is a horizontal concave rib provided in the waist portion of the body, and the sign (b) denotes vertical reinforcing ribs.

[0006] A certain level of buckling strength can be maintained in the above-described bottle (Aa) because reinforcing ribs (b) are provided along the horizontal concave rib (a). Since, however, both sides of each reinforcing rib extend straight vertically, the upper end (b1) and the lower end (b2) of the reinforcing rib (b) form narrow connections with the horizontal concave rib (a), and these connections are found weak in stress transmission. Stress would be concentrated on these connections, thus causing the problem that makes it impossible to enhance the buckling strength further. Especially when the amount of a resinous material used has to be reduced to save the material, the bottle body would have a less thickness and a lower buckling strength than before. Therefore, the concentrated stress created another problem, i.e., a limitation in weight reduction.

SUMMARY OF THE INVENTION

[0007] The object of this invention is to provide reinforcing ribs of such a structure that further enhanced buckling strength can be obtained for the horizontal concave rib around the bottle waist when these ribs are disposed in the waist portion of the bottle body.

[0008] This invention is characterized by a bottle configuration comprising:

[0009] A bottle composed of neck, shoulder, body, and bottom, said body consisting of an upper body, a lower body, and the waist between the upper and lower bodies;

[0010] A horizontal concave rib forming itself into the waist and consisting of a concave wall connected to the lower end of said upper body is, a concave wall connected to said lower body, and the bottom of the concave between these upper and lower concave walls; and

[0011] Reinforcing ribs, which are disposed in the vertical direction at regular intervals along the circumference of said horizontal concave rib;

[0012] Wherein said vertical ribs are designed to be narrow in the central part and wide at either or both ends, where each vertical rib is integrated with the peripheries of the concave walls of said horizontal concave rib.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a front view of the bottle in the first embodiment of this invention.

[0014]FIG. 2 is a cross-sectional view taken from line A-A of FIG. 1.

[0015]FIG. 3 shows a vertical cross-sectional view of the reinforcing rib.

[0016]FIG. 4 is a front view of the bottle in the second embodiment of this invention.

[0017]FIG. 5 is an explanatory diagram of a bottle in prior art.

[0018]FIG. 6 shows explanatory diagrams of the bottle-analyzing shapes.

[0019]FIG. 7 is a graph showing the results of an analysis.

DETAILED DESCRIPTION OF THE INVENTION

[0020] This invention is further described by making reference to the drawings.

[0021] In FIG. 1, (A) is a PET bottle molded by the bi-axially oriented blow molding, and consists of neck 1, shoulder 2, body 3, and bottom 4.

[0022] The neck 1 is provided on its outer circumference with a widened ring 5 and a neck ring 6. Under the neck ring 6, the bottleneck has an enlarged diameter and connects with the shoulder 2.

[0023] The body 3 consists of upper body 7, lower body 8, and the waist 9 between the upper and lower bodies 7 and 8.

[0024] The upper body 7 is provided with several horizontal ribs 10 having a round cross-section. A terrace portion 11 is formed between the upper body 7 and the waist 9 and has a wider diameter than the remaining portion of the upper body 7.

[0025] The lower body 8 has a wider diameter than the upper body 7, and is provided with several arc walls 12, which serve as the support for the bottle body, and with vacuum-absorbing walls 15 consisting of inclined walls 13 and flat recessed walls 14, with each vacuum-absorbing wall being arranged between two adjacent arc walls.

[0026] As shown in FIGS. 2 and 3, the waist 9 comprises a horizontal concave rib 16. Along its upper peripheral circumference, the rib 16 connects with the terrace portion 11 of the upper body 7, and along the lower peripheral circumference, the rib 16 connects with the lower body 8.

[0027] In the cross-sectional shape, this horizontal concave rib 16 consists of upper and lower concave walls 16 a and 16 b and a gently curved bottom 16 c. The bottom 16 c is provided with two narrow ridges extending along the circumference of the horizontal concave rib 16.

[0028] The horizontal concave rib 16 is also provided with multiple reinforcing ribs 18 extending in the vertical direction and disposed circumferentially at regular intervals.

[0029] At its upper end 18 a and lower end 18 b, each of the reinforcing ribs is integrated with the peripheral portions of the concave walls, 16 a and 16 b, respectively, of the horizontal concave rib 16. In the central part 18 c, the reinforcing rib has an outward rise for a certain length from the concave walls of the horizontal concave rib 16, so that the ridge of the vertical rib 18 forms a shallow arch in its side view.

[0030] The reinforcing ribs are wide at their upper and lower ends 18 a and 18 b; and they are narrow in the central part 18 c. On both sides where the reinforcing rib 18 comes in contact with the horizontal concave rib 16, the rib 18 forms the concave lines, and in its front view the rib looks like the upper and lower arms of cross formée.

[0031] In this embodiment, width of the rib 18 at both ends, 18 a and 18 b, is about 2.4 times as much as the width in the central part.

[0032] A horizontal rib 19 is disposed at the lower end of the lower body 8 and connects to the bottom 4.

[0033] The bottom 4 comprises a bottom ring portion 20 and a central conical wall 21 rising up from the ring portion 20. The conical wall 21 is provided with multiple, publicly known, radially arranged reinforcing ribs 22.

[0034] The action and effect are now described for the horizontal concave rib 16 and the reinforcing ribs 18, both of which are disposed around the waist 9. The horizontal concave rib 16 serves to increase the toughness of the body 3, and to get easy hold of the bottle.

[0035] In addition, the reinforcing ribs 18 are provided in the waist 9. The upper and lower ends of each of the reinforcing ribs 18 are integrated with the respective upper and lower peripheries of the concave walls of the horizontal concave rib 16. The reinforcing ribs 18 are designed to have wider ends than in the central part so that stress is dispersed and the buckling strength is enhanced at both of the upper and lower ends, 18 a and 18 b.

[0036] A varied embodiment of reinforcing ribs is now described, wherein the ribs of a different shape are disposed along the horizontal concave rib in the waist 9.

[0037] In the previous embodiment, the reinforcing ribs have wider upper and lower ends than in the central part. In this embodiment, the reinforcing ribs have only the wide lower end.

[0038] Except for this change, the bottle in this embodiment is identical with the bottle in the first embodiment. Thus, only the configuration associated with the reinforcing ribs is described below.

[0039] As shown in FIG. 4, the waist of bottle B has the same horizontal concave rib 30 as in the previous embodiment. The reinforcing ribs 31 are disposed within the horizontal concave rib 30 at regular intervals.

[0040] At its upper end 31 a and lower end 31 b, each of the reinforcing ribs is integrated with the peripheral portions of the concave walls 30 a and 30 b, respectively, of the horizontal concave rib 30. In the central part 31 c, the reinforcing rib has an outward rise for a certain length from the bottom surface 30 c of the horizontal concave rib 30, so that the ridge of the vertical rib 31 forms a shallow arch in its side view.

[0041] The reinforcing ribs 31 are wide at their lower end 31 b, where the rib 31 is integrated with the lower periphery of the horizontal concave rib 30, and are narrow in the area ranging from the central part 31 c to the upper end 31 a, giving the reinforcing ribs a shape of the lower arm of cross formée in its front view.

[0042] The action and effect are now described for the horizontal concave rib 30 and the reinforcing ribs 31. Since the reinforcing rib 31 is integrated with the lower periphery of the horizontal concave rib 30 along the wide lower end 31 b, this wide connection between the lower end 31 b and the lower periphery of the horizontal concave rib 30 allows stress to be dispersed so that the buckling strength of the body 3 can be enhanced.

[0043] The buckling strength of the reinforcing rib structure according to this invention is now explained on the basis of a strength calculation analysis.

[0044] The buckling strength was calculated for the bottle A in the first embodiment of this invention and for the bottle B in the second embodiment, and the results were compared with the buckling strength of a conventional bottle Aa.

[0045] For the convenience of analysis for bottle waist, the reinforcing ribs were assumed to have such shapes as shown in FIG. 6.

[0046] In FIG. 6, Aa1 shows the bottle shape analyzed for the waist portion of a conventional bottle Aa; B1, the shape analyzed for bottle B in the second embodiment of this invention; and A1, the shape analyzed for bottle A in the first embodiment of this invention. The resinous material used was PET (having a Young's modulus of E=350 kg/mm² and a Poisson ratio of □=0.35). The conventional bottle Aa and the bottles A and B in the two embodiments of this invention were given the same dimensions for the diameters of upper and lower bodies and for the diameter and height of the waist. Thus, the strength calculation was conducted for the bottle waist, assuming uniform sizes for all types of bottles, including an upper body diameter of 88 mm, a lower body diameter of 105 mm, a concave bottom diameter of 78 mm for the horizontal concave rib, a reinforcing rib height of 26.8 mm, and a thickness of 0.333 mm.

[0047] The strength test involved fixing the lower portion of each test bottle and applying a compressive force from above. The buckling strength was calculated by obtaining the quantity of deformation in the top portion of the test bottles.

[0048] As a result, an analytical graph, such as shown in FIG. 7, was obtained. X, Y, and Z are the points of intersection in the equilibrium curves obtained before and after the buckling which has taken place in the waist of bottles Aa, B, and A, respectively. Thus, buckling occurs at such a point of intersection or a turning point for each bottle.

[0049] A test bottle Aa1 was manufactured and tested. It had a buckling strength of 35 kg. This value was used as the buckling strength at Point X, and the analytical values were converted to give a graph shown in FIG. 7, wherein the graph was depicted from the levels of buckling strength versus the level of deformation. The level of buckling strength for bottles A and B, obtained from the graph, are as given in the following table. TABLE 1 Buckling strength A comparison with prior art bottle Bottle Aa 35.0 kg Bottle B 46.7 kg Up 33.4% Bottle A 95.4 kg Up 172.6%

[0050] From the foregoing results of analysis, it is obvious that the reinforcing ribs are highly active and effective because the bottle B in the second embodiment has a buckling strength of more than 40 kg, up 33% from the conventional bottle Aa; and because the bottle A in the first embodiment had a buckling strength of more than 90 kg, up 172.6%.

[0051] The reinforcing ribs are disposed in the vertical direction along the circumference of the horizontal concave rib at regular intervals. These reinforcing ribs are designed to be narrow in the central part and wide at either or both of the upper and lower ends, where each vertical rib is integrated with the peripheries of the horizontal concave rib. As a result, it has become possible in this invention to lessen the stress and enhance the buckling strength at either or both ends of each vertical rib. 

1. A structure of reinforcing ribs disposed circumferentially around bottle body, which is characterized by a configuration comprising: A bottle composed of neck, shoulder, body, and bottom, said body consisting of an upper body, a lower body, and the waist between the upper and lower bodies; A horizontal concave rib forming itself into said waist and consisting of a concave wall connected to the lower end of said upper body, a concave wall connected to said lower body, and the bottom of the concave between these upper and lower concave walls; and Reinforcing ribs, which are disposed in the vertical direction at regular intervals along the circumference of said horizontal concave rib; Wherein said vertical reinforcing ribs are designed to be narrow in the central part and wide at either or both ends, where each of said ribs is integrated with the peripheries of concave walls of said horizontal concave rib.
 2. The structure of reinforcing ribs disposed circumferentially around bottle body, according to claim 1 , wherein said vertical reinforcing ribs are designed to be narrow in the central part and wide at both of the upper and lower ends where each reinforcing rib is integrated with the peripheries of said concave walls.
 3. The structure of reinforcing ribs disposed circumferentially around bottle body, according to claim 1 , wherein said vertical reinforcing ribs are designed to be narrow in the central part and wide at either of the upper or lower end where each reinforcing rib is integrated with the peripheries of said concave walls. 